Abstract: A pipeline cultivation test platform based on ultrasonic atomization was built to study the effect of wind speed, atomization amount and temperature difference on settlement of nutrient solution fog in the pipeline. The influence of wind speed, atomization amount and temperature difference on the fogging amount in the pipeline was analyzed by single factor experiment, the order of factors were obtained by quadratic regression orthogonal rotation combined test, and the regression equation of the settlement amount of nutrient solution was established. The results show that: as the amount of atomization increased, the amount of settlement generally increased. When the atomization amount was lower than 420 mL·h^-1, the settlement amount increased slowly, and when the atomization amount was more than 420 mL·h^-1, the settlement amount increased significantly. As the wind speed increased gradually, the settlement amount decreased continuously, the wind speed was 1.1 m·s^-1, the settlement amount was the largest. When the wind speed was more than 1.5 m·s^-1, the settlement amount decreased significantly. The settlement amount changed approximately symmetrically with the positive and negative levels of the temperature difference, the absolute value of the temperature difference increased, and the settlement amount increased. The R² of the regression model was 0.734 7, and the model fitted well. The effects of three factors on the settlement of vegetable roots were as follows: atomization amount>wind speed>temperature difference. The maximum settlement amount was 0.063 g, the optimum combined atomization amount was 680.11 m L·h^-1, the wind speed was 1.34 m·s^-1, and the temperature difference was 0.039 ℃ in the model. The model was verified when the atomization amount, wind speed and temperature difference were: 660 mL·h^-1, 1.5 m·s^-1, 0 ℃, 540 mL·h^-1, 1.3 m·s^-1, 0 ℃, 540 mL·h^-1, 1.7 m·s^-1, 0 ℃, the settlement amount was determined by regression model to be 0.062, 0.060, 0.056 g, and the measured values were 0.057, 0.056 and 0.051 g. The relative errors were 8.77%, 7.14% and 9.80%, respectively. The results provided a reference sequence for the rapid and effective adjustment of the root growth environment, provided a reference method for the study of other environmental factors of the root system, and provided a reference for studying the root environment in other shapes of the aeroponics device.

Key words: ultrasonic atomization, cultivation pipeline, atomization amount, wind speed, settlement amount